Mark-detecting system

ABSTRACT

A mark-detection apparatus having a plurality of photodetectors for receiving light reflected from a plurality of points on an object such as a ticket and wherein a signal is generated representing the difference between the light detected by each of the photodetectors to indicate if a ticket has been altered.

United States Patent Inventor John William Donohoe South Natick, MISS.

Appl. No 10,772

Filed Feb. 12, 1970 Patented Sept. 14, 1971 Assignee DennisonManufacturing Company F ramingham, Mass.

MARK-DETECTING SYSTEM References Cited UNITED STATES PATENTS 2,825,8183/1958 Richardson 250/219 DC 3,517,167 6/1970 Bell 235/6l.ll R 3,525,8698/1970 Gubisch 2135/61.] 1 E 7 Primary ExaminerDaryl W. CookAnorneys-Sewall P. Bronstein and Donald Brown ABSTRACT: A mark-detectionapparatus having a plurality of photodetectors for receiving lightreflected from a plurality of points on an object such as a ticket andwherein a signal is generated representing the difi'erence between thelight detected by each of the photodetectors to indicate if a ticket hasbeen altered.

7a LIGHT 24 INPUT r o PosITIoN "A" SCHM'TT I| m X TRIGGER \I 260 LIGHTDIFFERENCE INPUT SIGNAL REFERENCE POSITION"R" DIFFERENCE SIGNAL [24bSCHMITT LIGHT IYc I| INPUT TRIGGER 2 26b 27b PosITIoN "B" 25b PATENIEUsEPI 41911 3.6041899 sum 1 0F 2 [We [l7b [I70 LIGHT LIGHT LIGHT DETECTORDETECTOR DETECTOR B I l I l8b I l8c l QIsu +v A lo l7 LIGHT 23 24 INPUTO PosITIoN"A" +M SCHM'TT |I| TRIGGER 17b 250 260 LIGHT DIFFERENCE INPUTSIGNAL REFERENCE POSITION"R" DIFFERENCE \SIGNAL [24 SCHMITT LIGHT I|INPUT TRIGGER gif 3T2?!) POSITION"B" 25b 7 INVENTOR BY John W, Dana/Icea I fl Vfiwnj ATTORNEYS PATENTEDSEPMIQYI 3604,8539

SHEET 2 0F 2 LIGHT llll POSITION A INPUT v2 POSITION "R" H6 5 TICKETTICKET EJECTOR 36b [IO {Ar 4o 4o @D4fi 6 g 42 PHOTOELECTRIC CELL FIG. 6

INVENTOR JO/an VV. Dona we BY q iln r:

ATTORNEYS MARK-DETECTING SYSTEM This invention is directed to an opticaldetection system and more particularly to a system for detecting thepresence of a mark on a ticket or the like.

Department stores and other merchandising outlets commonly use ticketswhich are affixed to the merchandise and have print thereon to indicatethe price as well as other information concerning the merchandise, e.g.color, stock no., etc.

In some of the newer merchandising systems using tickets, the ticketsnot only contain printed information as noted but in addition, containmachine readable information such as magnetic markings to facilitaterapid processing of the ticket.

These tickets, attached to the merchandise, are then generally collectedby the sellors agent as the merchandise is paid for at the checkoutcounter. The tickets are then subsequently utilized to maintain arunning inventory at the particular merchandising outlet, so as todetermine when merchandise should be reordered, and what merchandiseshould be stocked, and other information.

Attimes the printed price on the ticket is altered by hand during a saleor because of damaged merchandise. Special handling of these remarkedtickets is generally necessary since the machine used to read thetickets will be reading erroneous machine readable information which isnot correlated with the remarkings. Therefore means must be provided topermit remarked tickets to be recognized and sorted out from ticketswhich have not been altered.

According to this invention, a scheme for accomplishing this is providedby the use of a ticket which includes selected areas to which pencilmark, or other mark, may be applied and by the provision of an opticalsystem for detecting the fact that a ticket has been remarked, to sortout the remarked tickets from the unaltered tickets.

In accordance with the preferred embodiment of the invention, the aboveis accomplished by providing means for detecting the presence of a markon a ticket by measuring the difference between the amount of reflectedlight detected from an unmarked reference portion of a ticket and theportion of the ticket which has been marked. The presence of a mark(dark color) on the ticket causes less light to be reflected than wouldnormally be reflected from an unmarked area on the ticket. The signalwhich is generated is then utilized to either indicate an error, stopthe machine, or eject the ticket so as to sort out the remarked ticketsfrom the other tickets.

In view of the above, it is an object of this invention to provide a newand improved means for detecting the presence of a mark on a ticket orthe like.

A further object of this invention is to provide a new and improvedmeans for sorting unmarked tickets from remarked tickets, or vice versa.

Another object of this invention is to provide means for deriving adifference signal indicating that a ticket or object has been altered,as for example, by the change of price on the ticket.

Other objects and advantages of the invention will be apparent to thoseskilled in the art from the following detailed description of thedrawings in which:

FIG. 1 shows a merchandising ticket which has been remarked;

FIG. 2 shows diagrammatically the photo-optics for detecting informationfrom the ticket;

FIG. 3 shows diagrammatically the position of fiber optic probes used inone of the embodiments for detecting information from the ticket;

FIG. 4 shows a schematic circuit diagram of the apparatus according tothe invention;

FIG. 5 shows a modification of the circuit of FIG. 4, including meansfor ejecting the ticket based on the information derived from theticket;

FIG. 6 shows another optical scheme for detecting information from theticket. detachable,

Reference should now be had to FIG. 1 which shows a ticket 10 of thetype which can be used in merchandising and inventory control systems.The ticket shown in FIG. I and a system for printing machine readableinformation as well as print on the ticket is disclosed in copendingapplication Ser. No. 787,294, filed Dec. 9, I968, now Pat. No.3,517,612, entitled Marking System in the name of Richard Stucchi, andassigned to the same assignee of this invention.

The ticket may comprise as shown a main portion 10a and two stubportions 10b and which may be detachable from the main body portion. Themain body portion, 10a of the ticket is preferrable provided with a pairof closed areas such as circled areas shown at A and B. These circledareas A and B are provided to permit the salesperson remarking a ticketto apply a pencil mark which may then be detected to indicate that theticket has been remarked. Depending upon the system utilized, area A canindicate the price change, whereas area B can indicate some otheralteration made on the ticket. Additionally, if desired, marks in bothareas A and B can be utilized as a double check, to indicate whether aticket has been remarked.

In addition the ticket 10 is preferably provided with a center hole at13 which is utilized as disclosed in the aforementioned patentapplication for locating the ticket, so that information may be writtenon magnetic media (not shown), which is positioned about the hole 13.Also, as disclosed in this application, a probe or a ticket injector maybe inserted within the hole 13 to eject the ticket and to throw it intoa bin when it is determined that a ticket has been remarked.

In FIGS. 2 and 3 there is disclosed a fiber optic system for providinglight to scan points A and B, as well as to provide light to scan areference position R (a position somewhere on the ticket where therewould normally be the absence of any marks).

The optical system comprises light pipes or fibers 14a, 14b and 140,(e.g. glass), for directing light from a light source shown at 15 to theportions of the ticket which are to be scanned. In addition, the opticalsystem includes fibers shown at 16a, 16b and 16c for detecting reflectedlight from the areas of the ticket being scanned.

Light detectors, such as photoelectric devices are shown at 17a, 17b andfor detecting reflected light provided thereto by the fibers 16a, 16band 16c. The fibers for carrying the light as well as for returning thereflected light to the detectors are combined in probes shown at 18a,18b, and 180, each having a lighttight outer housing. Each of the lightpipes or fibers in the probes are also preferably surrounded bylighttight wrap or cover to prevent crosstalk between the two lightpipes of each probe.

Reference should now be had to FIG. 3 which shows a preferredarrangement of the reference probe and in the scanning probes withrespect to the ticket. It should be noted that the reference probe ispreferably somewhat offset, or out of line with the probes 18a and 18bto lessen the possibility of interference between probes.

In FIG. 4 there is shown a schematic diagram of a circuit for deriving adifference signal to indicate the presence of a mark in either area A orarea B of the ticket. The circuit includes light detectors, such asphotoelectric detectors, 17a, 17b and 170 which are responsive to lightreflected from the ticket into the light pipes 16a, 16b, and 16c. Thecurrent through the detectors 17a through 170 increases with an increasein received light and decreases with a decrease in received light andthe voltage across the photodetector varies inversely to the currentflowing therethrough. Accordingly, the presence of a black mark, (whichdoes not reflect as much light off the ticket as does a white area)causes the voltage across the detector to increase because the detectorrepresents a larger value of resistance. Each of the photoelectricdevices are connected in a bridge network and to operational amplifiersto derive a difference signal indicating the presence of a mark. Inparticular, electrical devices 170 and 17b are coupled to resistors 20aand 20b respectively, both coupled to a bias source +V. The points 21aand Zilb are then coupled through resistors 22a and 22b to the plus andminus inputs of a dual input operational amplifier 23a. Thus when a markis present, there will be a large difference between the inputs to theoperational amplifier 23a and therefore a difference signal will beobtained indicating the presence of a mark. The difference signal isprovided to a level detector such as Schmitt Trigger 24a, which thenturns on. The turning on of the Schmitt Trigger 24a causes a current toflow through a relay coil 25a thereby closing a switch 26a which causeserror light or indicator 27a to turn on, indicating that a ticket mustbe removed because it is a remarked ticket. In addition, the differencesignal could be used to stop the machine if tickets are moving throughthe machine, so as to permit the operator thereof to remove the ticket.The circuitry for detecting the presence of a mark in position B on theticket is the same as the circuitry shown for detecting the mark in areaA. Photodetector 17c is coupled through a bridge resistor 20c and pointZllc is coupled through a resistor 22c to an operation amplifier shownat 23b. In like manner a difference signal is obtained which is used totrigger a Schmitt Trigger 24b to cause current to flow in coil 25bclosing switch 26b and turning on the indicator light 27b.

With the circuit shown in FIG. 4 ambient light conditions will notsubstantially affect detection of a mark in the areas A or B, becausethe reference signal and the signal from the areas A or B which appliedto the operational amplifier from the bridge circuit will be trackingeach other. That is both the reflected reference signal and thereflected signal from areas A or B will be changing in the samedirection as ambient light changes, or as the components age. It shouldbe understood, that this system can be operated using ambient light, andinstead of detecting marks, the areas A and B could be punched out andthe information thus provided can be used in a like manner.

It will be understood that the circuit shown in FIG. 4 may varyaccording to the particular application. The following circuitspecifications are included for the circuit of FIG. 4 by way of exampleonly; V=6 volts, Photodetectors ll'7a17c-Motorola type 300, Operationalamplifiers 23a and 23b-Texas Instruments, Type SN 727, and Resistors 20aand 20c=51 K ohms.

Reference should now be had to FIG. 5 which shows a modification of thecircuit of FIG. 4. The photodetectors are shown at 3th and 31respectively and are connected in a bridge circuit with resistors 32 and33. The photoelectric detector has its emitter attached to a positivepotential instead of being grounded as in the circuit of FIG. 4. Thusthe voltage applied to the positive terminal of the operationalamplifier 34 is less than what would normally be the case andaccordingly, the operational amplifier provides a negative outputsignal. Assuming now that the amount of reflected light significantlydecreases because of the presence of a mark the voltage to the positiveterminal to the operational amplifier will therefore significantlyincrease so this now causes the operational amplifier to switch over andto provide a positive output signal which is used to turn on a poweramplifier 35 which causes current to flow through a solenoid 36, havinga coil 36a which then causes a ticket ejector 36b, normally in aretracted position, to rise and kick out the ticket MI.

The ejector is provided with a tip which enters the hole 1 .3 in theticket and causes the ticket to be ejected as the crosspiece portion ofthe ejector engages the bottom of the ticket. In this manner, a ticketis ejected from a line of tickets moving upon a machine bed.

Reference should now be had to FIG. 6 which shows a modified embodimentof the photo-optics for deriving reflected signals from the ticket. Inthis figure the ticket is again shown at and is positioned on a machinebed over which it is adapted to move. An example of a mechanism formoving tickets over a machine bed is shown in the aforementioned patentapplication referred to in the beginning of this specification. Themachine bed is provided with a plurality of openings shown at 40a whichare positioned to permit the areas A, B and R on the ticket to bescanned. Light 15 provided through a light source and light directorarrangement shown at 41 and is detected through a photoelectric cellarrangement shown at 42 which is responsive to deflected light. Thephotodetectors are then coupled as for example in the arrangementpreviously disclosed to indicate the presence of a mark on the ticket.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description are officially obtained and thatcertain changes be made in the above instructions without departing fromthe spirit and scope of the invention. It is intended that all mattercontained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

It should also be understood that the following claims are intended tocover all generic and specific features of the invention hereindescribed and that all statements of the invention which are a matter oflaw, which might be said to fall therebetween.

I claim: I

11. A mark-detection system for a ticket reader or the like wherein theticket used in the system includes an area for ap plying a mark theretoand an area where no marks are to be applied thereto, said systemcomprising first means for detecting light reflected from the area onthe ticket where a mark is to be applied, second means for detectinglight reflected from the area on the ticket where a mark is not normallyapplied, and third means responsive to signals from said first andsecond means for deriving a signal, indicating a difference in theamount of detected light.

2. A system according to claim 1 wherein said first and second means arearranged in a bridge circuit and wherein said third means is coupledacross said bridge circuit to detect voltage changes across said firstand second means as a result of changes in detected light.

3. A system according to claim 2 wherein means is provided to directlight against the ticket.

4. A system according to claim 1 including fourth means responsive tosaid signal for indicating that the ticket has a mark thereon.

S. A system according to claim 1 including ejection means responsive tosaid signal for ejecting a ticket from the machine upon the detection ofa mark on the ticket.

6. A mark-detection system comprising first means positioned to detectlight from a plurality of different positions on an object, second meansfor comparing the amount of light detected from sad plurality ofdifferent positions on the object to generate a signal indicating adifference in detected light from said plurality of positions.

7. A system according to claim 6 wherein third means responsive to thesignal is activated upon the detection of a mark placed on the object topermit the ticket to be removed from a group of tickets being read.

8. A system according to claim 7 wherein said third means comprisesmeans for ejecting the object from the detection system.

9. A system according to claim 7 wherein said third means compriseserror-indicating means.

10. A system according to claim 6 wherein said object comprises a ticketand wherein said means for comparing comprises an operational amplifiercoupled to said second means.

1. A mark-detection system for a ticket reader or the like wherein theticket used in the system includes an area for applying a mark theretoand an area where no marks are to be applied thereto, said systemcomprising first means for detecting light reflected from the area onthe ticket where a mark is to be applied, second means for detectinglight reflected from the area on the ticket where a mark is not normallyapplied, and third means responsive to signals from said first andsecond means for deriving a signal, indicating a difference in theamount of detected light.
 2. A system according to claim 1 wherein saidfirst and second means are arranged in a bridge circuit and wherein saidthird means is coupled across said bridge circuit to detect voltagechanges across said first and second means as a result of changes indetected light.
 3. A system according to claim 2 wherein means isprovided to direct light against the ticket.
 4. A system according toclaim 1 including fourth means responsive to said signal for indicatingthat the ticket has a mark thereon.
 5. A system according to claim 1including ejection means responsive to said signal for ejecting a tiCketfrom the machine upon the detection of a mark on the ticket.
 6. Amark-detection system comprising first means positioned to detect lightfrom a plurality of different positions on an object, second means forcomparing the amount of light detected from sad plurality of differentpositions on the object to generate a signal indicating a difference indetected light from said plurality of positions.
 7. A system accordingto claim 6 wherein third means responsive to the signal is activatedupon the detection of a mark placed on the object to permit the ticketto be removed from a group of tickets being read.
 8. A system accordingto claim 7 wherein said third means comprises means for ejecting theobject from the detection system.
 9. A system according to claim 7wherein said third means comprises error-indicating means.
 10. A systemaccording to claim 6 wherein said object comprises a ticket and whereinsaid means for comparing comprises an operational amplifier coupled tosaid second means.